An absolutely safe and dependable homologous blood supply is currently unattainable. Proper technique can reduce the associated risks of homologous blood infusion, but complete safety is not yet attainable. Autotransfusion (the collection, filtration and reinfusion of the patient's own blood or blood products) is rapidly becoming an accepted adjunct in the treatment of vascular, cardiac, orthopedic and trauma patients. The American Medical Association, American Red Cross, and American Association of Blood Banks promote autologous blood transfusion as the "method of choice" in blood transfusion.
A known blood conservation system is marketed under the trade name "SULCOTRANS" by Sulco Basle, Inc. of Rockland, Md. This known system utilizes a rigid graduated collection reservoir and sterile single use drainage tube sets. However, reinfusion is direct from the collection reservoir. This prior art system collects liquid from the patient body by vacuum or gravity. However, the suction source is the conventional hospital wall suction outlet regulated to 80-100 mm. of mercury suction. Reinfusion is by gravity or handbulb attachment and a standard blood administration set can be used for reinfusion. The prior system uses a 260 micron pre-filter to clean liquid coming into the collection reservoir and uses a 40 micron post filter for liquid coming out of the collection reservoir and going toward the patient. The prior device is intended for use in post operative collection of surgical site drainage blood for auto-infusion.
U.S. Pat. Nos. 4,569,674 and 4,655,754 assigned to assignee of the present invention, disclose wound drainage apparatus usable during and after surgery, wherein a portable base unit includes a battery pack, a vacuum pump, and means for controlling operation of the vacuum pump. A portable reservoir is releasably insertable into the base unit. Upon insertion into the base unit, the reservoir is connected to the vacuum pump through a check valve and hydrophobic filter to prevent the vacuum pump from ingesting liquid from the reservoir. The reservoir in turn is connectable through a check valve to a draining wound on a patient. The vacuum pump responds to the physical presence of the reservoir in the base unit and to the gas pressure within the reservoir for maintaining the gas pressure in the reservoir at a desired range below atmospheric pressure. The reservoir is releasable from the base unit and, upon such release, maintains vacuum (sub-atmospheric pressure) therein. Thus, the reservoir, whether or not connected to the base unit, when at a sub-atmospheric pressure, can draw liquid from a wound. In one unit a flexible member atop the reservoir visually indicates the presence of a sub-atmospheric pressure in the reservoir by its physical shape (it dimples when the reservoir is at sub-atmospheric pressure).
The present inventors have recognized that the wound drainage system of above-mentioned U.S. Pat. Nos. 4,569,674 and 4,655,754 could desirably be adapted to, or form the basis for, a blood conservation system.
Accordingly, the objects and purposes of the invention include provision of the blood conservation system which is usable for receiving blood from a patient and for returning the blood or components thereof at some time thereafter to the patient, which is capable of separating lipids and the like from the patient's blood before returning it to the patient, which can draw liquid from a surgical site on a patient after a surgical procedure by suction and without need for connection to the conventional fixed suction sources incorporated in hospitals, which can be implemented with a liquid reservoir capable of connection to and disconnection from a portable base unit incorporating a battery source and vacuum pump, in which the reservoir can be at sub-atmospheric pressure for drawing liquid from the surgical site both when connected to the portable base unit and for a time following disconnection therefrom, and in which the reservoir is usable with a known and readily available portable base unit.
Further objects and purposes of the invention will be apparent to persons acquainted with apparatus of this general type upon reading the following description and inspecting the accompanying drawings.